ActiveMQEndpointWorker could not stop quickly with a incorrect connector ip/port setting on AIX platforms

Details

Description

If the incorrect connector ip/port is set, on AIX platform, it takes a long time to stop it.
While in windows machines, it behaviors much better. From the code, there is no explict deadlock, I think that it is may be caused by the different thread scheduler on different OS platforms. Anyway, I try to add a flag in the code, it will make the ActiveMQEndpointWorker stop quickly.
Please help to review the patch, thanks !